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Science

Why Bubbles in Guinness Fall 202

Posted by CmdrTaco from the thats-pretty-cool dept.
ts4z writes "Reuters reports: 'Australian scientists say they have answered a question that has plagued and entertained drinkers for generations -- why do the bubbles in a glass of Guinness appear to be falling to the bottom?' I found the full story on Yahoo. Explains my endless facination with the stuff. " Hah! Beer and science working together. It's beautiful.
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Why Bubbles in Guinness Fall More

Why Bubbles in Guinness Fall

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  • i'm not sure was this was so incredibly difficult to figure out. i mean, check out your local lava lamp sometime. it does the exact same thing.

  • Not entirely. The 'lava' in your lamp falls back as it cools:)

    signature smigmature
  • hehe.. yup.. so guiness is good beer, and the bubbles fall, and someone found out why. so err uhm. Not much to discuss, just pass a pint :)
  • I'm going to go purchase some right now. Thankfully, on/off liquor stores don't have to close until midnight in Wisconsin. Let's hear it for the union of beer and science!

  • X-ScreenSaver candidate (Score:4)

    by Onetus ( 23797 ) on Tuesday January 11, 2000 @06:12PM (#1381412) Homepage
    Personally, I think this is the ideal candidate for a screen saver - since none of the Guiness or other beers have Linux versions of their screensavers. I could sit and watch the bubbles fall for hours..

    Perhaps their could be options to alter the consistency of the beer, from Guiness to Beamish to Ales... and so on.. with different bubble patterns.

    Truly this would be a great feat.
  • Doesn't this comply directly with the First Law of Beer?
    What froths up must go down, smoothly.

    -- Yoru

  • Why? (Score:3)

    by 1DeepThought ( 118171 ) on Tuesday January 11, 2000 @06:13PM (#1381414) Homepage
    So this is where my Australian tax dollar is going. Warms the heart doesn't it? Sort of funny I guess but hardly real science. Is there a practical use for this study? I can't think of one. Anyone got an idea?

    "Patience is a virtue, afforded those with nothing better to do" - I can't remember

  • Not really - lava lamps work by convection. The bulb at the bottom heats up the goo, which rises, away from the source of heat. When it cools off, it goes back down. The liquid in which the goo is suspended is designed so that it is just slightly less dense than cool goo and more dense that hot goo.

  • It's amazing really. In my own very unscientific studies, both bubbles and all the rest of Guinness seem to fall directly to the bottom of my stomach and just as mysteriously, suddenly rise straight to my brain !

    I must perform more thorough research into this however before submitting my paper to the journals...
  • It's advertising for the Fluent Fluid Dynamics software. If you read the yahoo article, it reads like a thinly veiled press release for the product.

    Good for a chuckle at bedtime anyhow...
  • Actually, it's not the same thing at all.
    The 'lava' in your lava lamp rises because it is heated by the lamp, and falls because it has cooled.

    The bubbles in guiness fall because Guiness is actually of alien origin, from a planet where the laws of physics are not exactly the same. The bubbles fall because they contain a denser-than-beer gas, give the scientific designation DTB01. The beer simply acts as a stabilizing agent.

    DTB01 has been shown to have other uses, especially as a method of powering interstellar and time-shifting spacecraft.
    Of course, these craft tend to use lava lamps as well, mainly to appease the crew, as they have nothing better to do, especially after drinking the leftover stabilizing agent.

    On another note, anyone remember how SGi has their patented method of doing random number generation, using a lava lamp and a digital camera? I believe it was for some e-commerce server they were selling at one time.



  • You know, I'm glad that I stayed up long enough to read that post. It gave me a good reason to take the short walk to the fridge and open myself some Guiness, which unlike some people in earlier posts, I keep a small stock on hand, in case of Y2K disasters and such.
  • Yes, Australians put the bubbles in there in the first place, so it stands to reason that they should understand them best.

    If you don't believe it, check out the movie Young Einstein [imdb.com]

  • What makes Guinness special? (Score:1)

    by Anonymous Coward
    What the report fails to explain is why Guinness is unique in having those mystical falling bubbles. Every loser worth his Stein knows that Guinnes is pressurized with nitrogen instead of carbon dioxide (hence the texture) -- is the nitrogen gas causing different bubble morphologies (ooo...) which subsequently behave differently in fluid flow? Or is it just that we don't notice the effect in lighter beers? Overall, I'm one unimpressed AC.
  • Actually, this is convection, too.

    In the lava lamp the convection is driven by a temperature gradient. Since the two fluids have a different thermal expansivity, which fluid's density is greater changes as a function of temperature.


    In this case, the bubbles have the same density and bouyancy, but different sized bubbles have different ratios of drag force to inertia. Therefore for some bubbles drag carries them along with the bulk motion of the fluid, while for others the bouyancy causes them to rise regardless.

  • I just found out the other day. I wanted Iced Tea (Nestea Lemon Iced Tea Mix), and I wanted to stir it fast, so I used a blender.

    Oddest thing, those bubbles falling like that. They were falling just like the Guinness bubbles.
  • Somehow this whole thing is going to end up with a long thread about beowolf clusters.
  • Now all we need to do is scientifically prove that Guinness is, in fact, good for you, in order to have reason to drink it more often. From the infamous ad campaign of the twenties and thirties: "the seven pints represent the seven beneficial resons for drinking Guinness: 'strenth, nerves, digestion, exhaustion, sleeplessness, its tonic effects, and for the blood.'" So I guess it has been proven -but does that mean that seven pints (a day) are required for optimal effects? I suppose there's only one way to find out, isn't there. I hereby volunteer myself as a test subject.

    --

  • I have no idea what any of you are talking about. I am under 21, and therefore know nothing about this Guiness of which all of you, who I assume are 21 or over if in America, speak.

    --Colbey

  • Ok, marvelling at how bubbles flow down is a bit strange, but hey, people are weird that way. It's funny, though: I like it when something is solved, but sometimes, it's nice when there's something that no one can explain YET. Nothing like a problem that no one has solved to get the brain working.
  • I suggest you also take anatomy. The beer would have to travel through your bowels to get into your brain, since the stomach does not touch any of the lobes or the stem.
  • Guiness is good jedi knight.

  • Guiness Unified Theory (Score:5)

    by RuntimeError ( 132945 ) on Tuesday January 11, 2000 @06:28PM (#1381430)
    Guiness Unified Theory - GUT ---------------------------- At the beginning of the Universe, there was Guiness, and there was a bubble. The bubble, unable to resist the temptation to go up, did so. Once it reached the top, it had to come down, so it did. T+2s: There is Guiness, and there is a bubble, going up and down. The other bubbles, realising that this bubble was breaking the state of equilibrium, decided to join it, in it is endless monotonous cycle. T+3s: There is a Guiness, and there are bubbles. The bubbles are in a state of equilibrium. Is this, the future of the universe ? T+300s: A guy comes along, and sees a Guiness, and he sees bubbles. He is fascinated by the bubbles going up and down. He is so fascinated, he decides to create the rest of the universe, the stars, the planets, the comets, and other celestial objects. T+5Days: The guy is still fascinated by the Guiness, and its bubbles. He finds nothing so interesting in the rest of the universe he has created, so he puts plants and animals, on some planets. T+6Days: There is the Guiness, and there are the bubbles, and there is the rest of the universe. Still, the Guiness, with its bubbles, is more interesting. The guy ponders, while watching the bubbles go up and bubbles go down, and decides to put intelligent being, in the form of himself, on of the planets. He calls that being 'Man'. T+6.5Days: There is a Guiness, and there are bubbles, there is the rest of the universe, and there is Man. The first guy, gets a bit thirsty. He looks at the Guiness, and unable to resist the temtation drinks it. T+7Days: There is no Guiness, and there are no bubbles, but there are stars, planest, moons and, then there is Man. The first guy, the guy who has been there from the beginning of universe, and who is now totally drunk, looks at the man, and, he feels that the man looks too happy, and content. Then, he creates a woman.

  • Duh. (Score:3)

    by jht ( 5006 ) on Tuesday January 11, 2000 @06:31PM (#1381432) Homepage Journal
    People spent money on this? It's always been obvious to me that each pint of Guinness represents a full-fledged microclimate, with convection and all. I'm surprised thunderstorms don't break out in it.

    Actually, thunderstorms have been know to break out in my head after drinking a large amount of it, but I don't think that counts.

    Heck, even I could have done this research. It would have been fun, too. I wonder how the effect changes as the level of stout in the glass drops...

    - -Josh Turiel

  • Damn! (Score:1)

    by El Rey ( 61125 )
    There goes my Guinness = cold fusion theory...

    Damn...

  • I love those little nitrogen widgets they put in them. It is nitrogen that makes the 'small bubbles' required for the creamy head and the downward flow (as the article points out, the bubbles must be less than than 0.05 mm for this).

    But the widgets themselves are a truly cool piece of engineering. They hold the nitrogen under pressure until the can is opened and then inject the gas into the beer through a hole so small it almost has to have been drilled by a laser.

    The first time I took a Guiness can apart was documented by my girlfriend on her Web Journal [halcyon.com]. We did some interesting web searchs for more information on the thing. Turns out the widget is patented, and only one of several versions of the same (all of which are patented). Apparently there was a fairly significant research effort by competing companies to re-create the correct creamy foam on canned stout.

    I think I speak for all of us when I say "Thanks! It was money well spent!"

    Jack

  • This is OLD news. Was on the Paul Harvey show last week.


    Did you guys hear, JFK got shot...
  • Don't give up I am yet to see any peer review of this study. However, I am considering taking on large quantities to test it myself.
  • A random number generator based off of a pint of guiness and a random number generator would take a lot of the tedium out of a sys admin job. Part of your responsibilities would be to make sure the generator stayed fresh, and disposing efficiently of the previous number generating pint
  • Ah, but we don't need any more test subjects for the non-control group %^)

    (oddly, the problem seems to be getting subjects for the control group.)

  • OPEN SOURCE BEER (Score:4)

    by Anonymous Coward on Tuesday January 11, 2000 @06:37PM (#1381441)
    starring:
    obi wan kenobi: a bottle of guiness.
    luke skywalker: mark hamill.

    luke: no, my father wasn't a bottle of zima, he was a can of budweiser!

    obi wan: that's what your uncle told you, he didn't hold with your fathers full flavor and smooth texture. thought he should have stayed in the vat and fermented longer. which reminds me, i have something for you. your father wanted you to have it when you were old enough, but your uncle wouldn't allow it. thought you might drink old obi wan and pass out in your own vomit.

    obi wan hands luke a large pretzel.
    luke: how did my father die?

    obi wan: a young man named busch, who was a brewer until he turned to evil, opened your father and let him sit for a week. busch was seduced by the dark side of alcohol.

    luke: alcohol?

    obi wan: alcohol is what gives a beer his power. it's a chemical created by the fermentation process that surrounds us and penetrates us and binds us together.


    luke gets a glazed look on his face, like suddenly has the urge to get roaring drunk.


    thank you.


    fat-time [warmann.com]!!
  • First, without them working together, there would be no 'scientific blends' of hops. But science and beer have worked togethre since beer's creation...what do you think spawned most of the Nobel prize winners?

    -"Billy Corgan, Smashing Pumpkins"
    "Homer Simpson, Smiling Politely"
  • Incase the rest of the world forgot our beer drinking Crocodile Dundee sterotype our scientists can remind them.
    That sterotype is completely untrue, I prefer to get wasted on Burgandy Rum.

  • I thought the First Law of Beer was:

    Beer you have is good beer.

  • After all, we're the country that figured out how to split the atom trying to put bubbles in beer [imdb.com] :)
  • B. E. E. R.
  • Yeah! The coolest thing is to inhale the nitrogen as it comes out - it makes you talk all squeaky!!

    The other alternative use for Guinness widgets is freezing stuff with the liquid nitrogen contained inside. Of course, you have to turn your fridge all the way up to 11 to get it cold enough.

    Does anyone else have any novel uses for the widget?

  • Re:Why? (Score:2)

    by pb ( 1020 )
    No, they only want you to think that. It's not even an ad for Guinness, or their book of records! Nay, 'tis much subtler and more sinister.

    It's an ad for TRANSPARENT GLASSWARE, put here by THE CHINESE MAFIA, to reduce American productivity, reducing us to ZOMBIES staring at beer bubbles FOREVER while they invade and seize our BEER PRODUCTION!

    The Evidence:

    The beer flows down instead of up. Therefore, it's on the other side of the planet. The Land Down Under, in fact. The mind-numbing effects of beer bubbles have already been demonstrated by the testimonials found here. And even though everyone knows that Australia was populated with criminals, my sources tell me that the Chinese Mafia are launching this as a counteroffensive, so that no one ever succeeds in that land war in Asia (by mesmerising the enemy troops with the beer bubbles, of course).

    So I should clearly not choose the beer in front of me...
    ---
    pb Reply or e-mail; don't vaguely moderate [152.7.41.11].

  • How about... (Score:3)

    by Anonymous Shepherd ( 17338 ) on Tuesday January 11, 2000 @06:48PM (#1381454) Homepage
    Sorting things according to size? If they can be suspended in a dense enough fluid, like Guiness, larger things will float to the top while the smaller objects cannot help but be carried away by the fluid flow.

    Now if you actually mixed this method with some sort of incremental generative process, then things that sink will eventually get larger, while the objects floating on the top can be scooped up for usage! Sorta wacky way of how snow is actually generated in our atmosphere; the wind keeps the water/ice/snow fragments suspended until they get too large or heavy and proceed to fall down.

    Just one idea

    -AS
  • alright, to all of you who replied to my original posts concerning the convection nature of lava lamps:

    the lava drops not because it is colder--that is only an indirect cause. the real reason is that it's relatively less dense when compared the the surrounding lava and fluid.

    same with the beer, people. the air carries it up. (there are issues of momentum, resistance, etc. which i won't discuss here). if the bubble (combination of gases and liquids which for now we'll consider as a unit) finds that it's density is greater than the surrounding, it will proceed downwards, but if it is lesser, then it will stay at the top. the critical size in this case is cited.

    but please, people, convection is just one way of changing the density. the fundamental problem can easily be seen in your lava lamp.

  • Now if we can get CmdrTaco and grammar working together, we might just have something!


  • damn, that clears that up. and all this time i thought it was just an article by yahoo to distract our attention while it flashes subliminal messages in the background. These subliminal messages most likely have statements like "kill kill kill", and "zip your pants back up", leading me to believe that my post is pretty fucking stupid to begin with and should be moderated down pretty low.

  • Bowels? (Score:2)

    by / ( 33804 )
    Alcohol is one of the few things (besides water) that permeates the stomach lining and enters the blood stream without going through the intestines. It's also one of the few things that'll permeate the blood-brain barrier and enter the brain without assistance. The humorous post that you responded to was quite correct in leaving out the bowels (albeit while leaving out the blood stream).
  • When I was a kid, I used to make "fake beer" by (carefully!) making Iced Tea Mix with either Sprite or Ginger Ale (Canada Dry, naturally).
    Tastes good, looks like lager, lots of sugar into your system.
    Geez, I think i should try making some with vodka one of these days...:)
    PS you don't use a blender for this, it will explode! Just stir carefully...

    Pope
  • Is this actually a valid study? The write up is very scant if it is :)

    I thought that the reason the bubbles in Guiness fell was that they contained a gas that was heavier than that in normal beer.

    From memory, Guiness contained Nitrogen, which makes it's bubbles heavier than the normal beer bubbles which contain Carbon Dioxide.

    I'm no chemist, but on the periodic table, Nitrogen is heavier than Carbon, so perhaps there is some truth in this :)

    As for the 'they go up, but then there's no room, so they go back down' theory.. wouldn't that happen in all beers?

    B.
  • I must admit that I have personally mutilated a few cans of Guiness to see what was inside. A true work of genius. It's almost as good as the real thing. It made me wonder why other beer makers hadn't done something similar and then it dawned on me -- obviously, they had patented the idea. At least it's a little more novel than 1-click shopping. I'm just glad that Amazon.com doesn't make beer. Then no one else would be able to open their beer w/o paying a royalty.

    As for the Guiness empire, I've heard that they plan to stop shipping bottles completely and just stick to the nitrogen cans. I think I can live with that.
  • Sure. It'd take a pretty big beowulf cluster to truly model the fluid dynamics accurately, even in a little pint of Guinness.

    However, the Guinness models it perfectly... amazing! Beer-based computing time!

    Seriously though, folks, there have been articles about using DNA for specialized problem-solving that would ordinarily take supercomputers a long time, and it involves basically sloshing the stuff around in a solution, and then looking through it later for the result. Neat stuff, that. So you're closer to the truth than you think.
    ---
    pb Reply or e-mail; don't vaguely moderate [152.7.41.11].

  • Since the air you're already breathing (presumably) is 70% nitrogen, and you don't talk squeaky (at least, no-one I know does), then I fail to see how you reached that particular conclusion. I think you have it confused with helium...

    BTW, there's no fridge built for the commercial market that could get low enough temperatures to liquify nitrogen (-176C?).

  • Yep, but I specifically didn't say that it was Nitrogen gas vs CO2. I said guinness CONTAINED Nitrogen, which is heavier than Carbon.

    I've also since read a post on here that talks about using the gas in the widgets in Guinness cans for various cool stuff. Again, I'm no chemist, but I doubt anyone would be too fascinated with playing around with plain old Nitrogen (N2) gas, which leads me to the conclusion that the gas released into guinness is something else...

    B.

  • Re:Have you ever taken a Guiness can apart? (Score:5)

    by Saurentine ( 9540 ) on Tuesday January 11, 2000 @07:29PM (#1381474) Journal
    I love those little nitrogen widgets they put in them. It is nitrogen that makes the 'small bubbles' required for the creamy head and the downward flow (as the article points out, the bubbles must be less than than 0.05 mm for this).

    But the widgets themselves are a truly cool piece of engineering. They hold the nitrogen under pressure until the can is opened and then inject the gas into the beer through a hole so small it almost has to have been drilled by a laser.

    I don't think that the little widgets actually hold the nitrogen in them throughout the shipping process. Without knowing the manufacturing details, it would make more sense that they put them in there with nitrogen in them, but they're frozen at the time of insertion. The can filling and capping process is done immediately afterward, very quickly. The hole is always there, and it cannot hold the nitrogen in the device during transit.

    Then nitrogen then thaws, pressurizing the can to a rather high equilibrium point and Guiness absorbs virtually all the nitrogen during shipping.

    When you open it, the pressure at the can's pop-top drops almost instantaneously, while the widget's tiny hole prevents the pressure from dropping as rapidly. The relative imbalance of pressures creates a brief but very energetic internal fountain of Guiness in the bottom of the can! The shearing forces of Guiness rubbing up against itself then releases much of the trapped gasses in the Guiness in dramatic fashion. This is why the foam up best when you crack the top quickly rather than breaking the seal slowly.

    I sacrificed a particularly noble can of Guiness to test this theory once by chopping it open with a very large thin-bladed adze and my observation was that the device was literally squirting Guiness and not venting gas.

    A very, very costly experiment indeed, but I had to find out what was going on in the magic can!
  • There's an archived page h ere [google.com] with a little more information on the Nitrogenising of beer, and the widget in guinness cans.

    B.
  • Recently, they've ditched the widget. In place there seems to be just a little plastic ball in there, although I haven't mutilated the can to see if there's any other goodies in there. It creates the same head, cascade and all, just probably cheaper to make.
  • The shape of the glass causes the bubbles to look like they're going down when they're really going up. Really now, unless being CRAMMED by a mass of other bubbles, where is the energy going to come from to push bubbles down? Since the bubbles are spaced by several radii, they're not being pushed down, and convection currents are no where near that high or there'd be a noticable "dip" in the center of the liquid. This entire Slashdot article is URBAN LEGEND.

  • I get it (Score:1)

    by Anonymous Coward
    I get it, I finally get it ... you all want relevant posts! .. why you narrow minded bigots!
  • there's also a ny times article [nytimes.com] on it. apparently, the Fluent software can be used in the "aerospace, chemical, electronics and automotive" industries as well. that and to predict the ever important turbulence inside beer/wine fermenters...
  • It's interesting that you should post such a story just I have finished consuming lots of... how do you say in America? Beer.

    I am rather fsck'd up, too. But don't hate me because I'm beautiful and more 3l337 h@x0r than you. Or however that goes. Your distro wars mean nothing to me anyway.

    I wish someone would post a beer haiku because I like beer and I like haikus and I think the two things put together would be funny except I don't know anything about haikus, except I do know a lot about beer if that helps. I like beer.

    I like porters especially. Sometimes a nice ale or stout; rarely a pilsner. Pilsners are for Winbl0ze and TI99/4a uZerZ. Sorry, nothing pers0n@al, d00dz.

    Beer. In the year 2000 and beyond. To infinity... and shit. I hate stupid cartoons.

    Some of the beer I had earlier was Guinness. It was so thick it was like drinking bread, only thicker. Then I had a Sierra Nevada Pale Ale. Does anyone else like beer like I do? I really like to drink me some beer.

    Does anyone else like wine - perhaps a little Riesling or Piesporter? Red wine, on the other hand, is like drinking Sour Patch Kids for me.

    I like beer.

    And Linux.

    --

  • Fluent, the CFD code that was used to do the simulation, has a version that runs on clusters. (We had combustion people doing it all the time on our cluster)

    So yes, this can be tied into a Beowulf.

  • Oh, this is a good science story (Score:1)

    by Anonymous Coward
    (RANT)
    Not that I don't like beer, or anything, but I submitted a great story this afternoon about how the Galileo spacecraft [nasa.gov] found very strong evidence for a Liquid water Ocean under the crust of Europa. And this gets posted instead... in the science section?! Maybe in the "Laugh its funny section," but the freaking science section... that and the Yahoo story isn't even that long... sure it point to a cool simulation page, but the news about the liquid ocean on the Jovian Moon story has far more information... being a fscking science story and everything
    Arg, Slashdot sure does suck.. glad there is the Post Anonymously button so the silly karma points don't go down.
    (/RANT)
  • Wonder if temperature enters into it. Australian's are reknowned for not enjoying their beer in any state but cold.

    Sign outside a bar in the backwaters of Indonesia (where Australian back-packers were often encountered :)

    "Yes, we serve fucking cold beer!"

    :)
  • For all the crap that we get about cows and cheese, it all comes down to that, doesn't it? Up to the wee hours writing some obscure piece of code that you won't understand in the morning but seems to do everything but bring world peace at the time you're writing it. You get thirsty and see that it's late at night...but wait! The gas station just a few blocks out of town still has its nuclear powered mini-sun lights glaring, and the beer cooler is still open. God, I love this state somedays.
  • 1) Fluid rises, under influence of all the rising bubbles.
    2) Fluid actually goes DOWN at the edges of the glass.. forming a kind of convection-like current (but it's not convection, of course.. just looks roughly similar)
    3) The *small* bubbles are carried downwards at the edges of the glass, in this current. Only the small ones.. not the big ones.

    Now.. this may make little sense, but remember, the presence of bubbles also causes the density of the fluid to go *WAY* down (detonating a mine underneath a battleship can cause the ship to snap in half.. simply because of the air bubbles produced underneat the ship... the remove the buoyancy and overstress the hull...)
  • Wait. No. Where did my moderator points go?

    I wanted to moderate my beer up.

    --

  • Guinness mixes "soured" beer in with its import draught at about 3% v/v. Souring is accomplished by inoculating a beer wort with lactobacillus bacteria, or, for those of us who don't have access to a microbiology lab AND who live in an area with a high airborne concentration of lactob's (such as Dublin), letting the wort sit open for a few days. Incidentally, this is why it is a bitch and a half for a homebrewer to "copy" Guinness. Thus, a possible reason for the unique behavior of Guinness bubbles is the different solvation environment accorded by the lactic acid produced by the bacteria. However, as any chemist worth his bathtub knows, carbon dioxide reacts with water to form carbonic acid (especially under pressure!), although the equlibrium for the reaction lies strongly with CO2. Who knows... the only other beer that I know of that contains lactic acid (other than my local zymurgist's frequently foul-tasting disasters) is Belgian lambic. It may be interesting to compare the bubble dynamics of Guinness with lambic, though prohibitively expensive if you live in America... decent lambic goes for $7-$12 a 12 oz. bottle, if you're lucky enough to find it stateside.

  • The Guinness Widget Explained (Score:5)

    by mindstrm ( 20013 ) on Tuesday January 11, 2000 @07:56PM (#1381491)
    Okay. The 'widget' in the can of guinness.. here goes.

    Guinness is brewed iwth a 75/25 mix of N2/CO2 (You know.. Nitrogen gas/Carbon Dioxide). CO2 apparently creates much more pressure when compared to dissolved Nitrogen... anyway...

    When the publician pours you a draught guinness, usually the guinness is passed through a filter with a few tiny pinholes in it.. this causes the beer passing through it to release it's nitrogen en masse, and causes that nice creamy head we all know and love.

    Now.. many say the 'widget' in guinness contains compressed gas, and releases that gas when the can is opened... but they, having had a few already, forget that beer (like water) doesn't compress really... and could not possibly hold a compressed widget closed... what really happens is this.

    The widget is a plastic container with a few very tiny pinholes laser-drilled into it. This is put in the can, the can is filled most of the way up with guinness, and a drop of liquid nitrogen is placed in the can, and then it is immediately sealed. As the liquid nitrogen turns to gas, the gas is absorbed into the beer, and also increases the pressure on the beer (by increasing the gas volume in the available space) causing liquid to be forced into the widget through those little pinholes.... under pressure. Now.. when the can is opened, some of the beer vacates the little widget, and by moving through these pinholes, acts similar to the bartenders filter, and causes more of the 75/25 n2/co2 mix to be released.. giving a nice, creamy head with strange properties.
  • It actually just fills up with guinness under pressure (after the can is sealed by the elves), and releases it when the pressure is released. The small laser-cut hole the guinness is released through 'knocks' the nitrogen and co2 (it's 75/25 n2/co2) out of solution and causes that nice creamy head.
  • Actually, it's not the guinness 'rubbing against itself' that releases the gasses, but the guinness travelling through the tiny, laser-cut pinhole in the widget (or ball, as it were)... it 'knocks' the gas out of solution.

    The gas is a 75/25 nitrogen/co2 mix.
  • ... you are attempting to take the mystery and beauty out of one of mankind's profoundest experiences. Your base, materialism fails to explain the dark loveliness of a blonde and tan tankard of voluptuous thirst-sating porter. The following is set as your penance (it also contains some excellent advice for students:

    'The Workmans Friend - Flann O'Brien/Myles na gCopaleen

    When things go wrong and will not come right,

    Though you do the best you can,

    When life looks black as the hour of night -

    A PINT OF PLAIN IS YOUR ONLY MAN.

    When money's tight and hard to get

    And your horse has also ran,

    When all you have is a heap of debt -

    A PINT OF PLAIN IS YOUR ONLY MAN.

    When health is bad and your heart feels strange,

    And your face is pale and wan,

    When doctors say you need a change,

    A PINT OF PLAIN IS YOUR ONLY MAN.

    When food is scarce and your larder bare

    And no rashers grease your pan,

    When hunger grows as your meals are rare -

    A PINT OF PLAIN IS YOUR ONLY MAN.

    In time of trouble and lousey strife,

    You have still got a darlint plan

    You still can turn to a brighter life -

    A PINT OF PLAIN IS YOUR ONLY MAN.

  • Re:you're all illegal! (Score:2)

    by Anonymous Coward
    Only in America, a 10 year old can pilot an airplane, but can't get a driver license; a 15 year old can have sex but can't rent a sex video; a 17 year old can join the army but can not buy hand gun; a 20 year old can get married but can not drink a beer; ...
  • Personally, I think this is the ideal candidate for a screen saver - since none of the Guiness or other beers have Linux versions of their screensavers. I could sit and watch the bubbles fall for hours..

    How is this software distributed? You have two options...

    If you make it Free, then you have created free beer, which RMS wouldn't like.

    If you make it non-Free, your software gets marked down as flamebait.

    Therefore, the screensaver cannot be successfully written and distributed.

    --

  • The last line of the article reads :

    Guinness is made by British-based Diageo Plc.

    And all along I thought that Guinness was made by Guinness... Shhh...
  • This is why I love Slashdot. Right here.

    I could bet the house a pint that none of you had a straight face when you added your helpful tidbit about convection-like currents and N2/CO2 ratios, and I'd win.

    On a serious note, I know at least fifty people who could stand to get up from their VDTs long enough to amble down to O'{whatever}'s and tip one back, preferably not alone.

    Here's to you guys...you made me laugh, and that's a blessing that goes way underappreciated, way too often. Thanks.
    _____

  • I believe he is. I remember something about this - digitizing pictures of a lava lamp and using them as seed values for random number generation. Apparently, lava lamps are really, really random.

  • Ah - found the link. Try looking here [sgi.com].

  • I agree with your sentiments.

    Before you moderate this as redundant, please at least do me the courtesy of reading all that I have to say.

    Lately, there's been a BIG kerfuffle in Australia with Telstra and their monopoly on broadband Internet access. On a more global scale, Governments everywhere have been declaring that violent computer games promote real life violence - something that most of us disagree with.

    I submitted two stories to Slashdot about it - at different stages in the battle against Telstra's ridiculously high prices, and have just submitted a story about the Australian Goverment actually getting something right and declaring the computer games DON'T create homocidal maniacs (since Australia's 'net censorship, and the way goverments all over the world have been blaming computer games for violent crimes), and I'm going to be very surprised if it makes it to the front page as a news item.

    And yet a story about someone wasting money on discovering why bubbles in Guinness seem to sink has been deemed to be "News for Nerds. Stuff that matters."

    Slashdot's standards are definately falling - I know it's been mentioned before, and people who have said so have been moderated down through the floor - but it's a sad day when news about bubbles in beer moving in unexpected directions is deemed to matter more than news about monopolies and their effect on freedom of access to the Internet, and the fact that at least somewhere in this crazy world a government has realised that playing Quake doesn't immediately turn you into a weapon of mass destruction.

    Like the other posts on this matter, this one will probably get moderated down to ridiculous depths as well - but I feel that this needs to be said, and I'm willing to risk my karma to give it a +2 head start before it vanishes into the ether.
  • From the article:
    Animation of the simulation is available at
    Just what the hell am I supposed to do with a simulation? I know what to do if I want to watch the bubbles in a Guinness!

    Funny, though. I can never manage to watch them for very long. *burp*

  • 21? Blimey. I was knocking back several pints of Guinness a night, legally, at the age of 18. Even at 16 it's legal here if you're drinking it with a meal...

    Mind you, the drinking age is 21 in Eire, so I guess for the proper Guinness experience...
    --
  • Please, let me take a moment of your time to recommend the less gassy members of the esteemed Guinness family.

    Draught Guinness (from the pub) is very nice, and all, but I never felt the DraughtFlow(TM) cans quite reached the same standard.

    ... so I drink Guinness Original, which you can get in cans or bottles, and which has a subtly different, more irony taste, without the creaminess. You can sometimes buy Guinness original in bottles in the pub, in which case you might be lucky enough to get the unpasteurised version. Yum.

    Alternatively, there's the gorgeous Guinness Foreign Export. In the last century (heh, the century before that, I s'pose) beer for export had to be brewed a little bit stronger, so it survived the long sea journey (hence India Pale Ale). Guinness Foreign Export is 7.5% alcohol by volume, and it's like drinking Marmite. Class in a glass (bottle) -- if you can get hold of it.
    --
  • The new bottle has a widget in it too. Each time you take a drink from the bottle, the widget releases a little bit more gas, thus keeping the head.

    Those guys in the Research Centre in Ireland sure have their heads screwed on the right way. Doing wonders for our wonderful products.

    As for good places to get Guinness in Ireland, here are a few that I know of:
    Dublin Airport
    Guinness Hopstore (let's face it, if you can't get a good pint of Guinness at the source, where else will you get one?)
    Lynches Pub (Thomas St., Dublin - just down the road from the brewery)
    Sheaf Of Wheat Pub, Coolock, Dublin (formally a Guinness owned pub)

    I'm sure there are a lot more too.

    I don't drink, so I can only go by what people tell me. But a lot of people who have drunk Guinness in Dublin Airport after flying home from a holiday have found it to be a delight to their taste buds.

    The secret to a good pint of Guinness is the way you pour the pint. Guinness isn't lager, and thus shouldn't be poured like lager. It shouldn't be poured too fast either. And the Gas mix has to be right. Most barmen in Ireland know this, but unfortunately in other countries they don't.

    Everyone knows that Guinness made in Ireland is the best in the world, but no too many realise that this same Guinness that is served in Irish pubs is also served in American pubs. Made right here in St. James's Gate.

    http://www.guinness.com [guinness.com] - you might even find the instructions on how to pull a proper pint.

    Oh, it officially takes 119.5 seconds to pull a proper pint of Guinness.


    T.
  • Guiness is one of those very rare items:
    a complete food. It contains, in trace amounts, all the minerals, vitamins, protein and carbohydrate that you need.

    However, in order to get enough of everything, a man of average size would need to drink 47 pints a day. But here's the catch: somehow I doubt you would stay an at an average size on this diet.
  • It would seem that this story is on it's way [slashdot.org].

  • No, 'strue! Guinness contains lots of iron, which led to doctors prescribing it to pregnant women a few decades ago.

    I pity all you foreigners, though, as you can only get a real pint of Guinness in Dublin (or in the Coach and Horses pub in Covent Garden, London, which imports it's Guinness from Dublin). And yes, it is better than the other stuff that's brewed in over fifty cities across the world...

    D.
    ..is for DRINK!!

  • I do beg your pardon. I must have gone to an "over 21s" pub, when I was in Ireland. Sorry.
    --
  • In the spirit of independant, scientific verification I propose engaging in a test of this supposed Australian "theory".


    After all, they're on the other side of the planet -- so wouldn't things that sink on this side rise in Australia?


    Does anyone have a few dozen pints of Guiness (the good English brew, not the bastardized version they export!) to give away for an experiment which will reveal the One Truth of Beer?

    Be careful how you respond,


  • No, 'strue! Guinness contains lots of iron, which led to doctors prescribing it to pregnant women a few decades ago.

    That's not *quite* true. It was prescribed to nursing women (i.e. after they had given birth).


  • I love Guinness. I live in New York City.

    I travelled to Ireland. I went to Dublin. I went to the Guinness factory and had a beer. I was in heaven.

    I travelled around the rest of Ireland. Drank only Guinness. Love love love.

    I came back to the states. I drank a Guinness....

    PTOOOOIIEEEE!!!

    Guinness in the USA sucks.

    Actually, I have to say that the bubbles are 'harder' and the taste is more bitter in non-IRL Guinness. How about a study on that?

    --

  • OK. We now know about Guiness, how about the Corona and lime affect?
    For those who don't know what am typing about, take a bottle of Corona and put it in your freezer. Remove the bottle before the beer freezes (we just want the beer to be really cold) and squeeze a little lime in it.
    What happens next is really cool. The beer will start to freeze from top down, forming some really neat crystals on the way.

  • Re:Why? (Score:4)

    by Malc ( 1751 ) on Wednesday January 12, 2000 @04:14AM (#1381552)
    Why does there have to be a practical use to research. In my mind, pure research (research for research's sake) is a good thing. It might seem irrelevant to some, it might not go anywhere. But then again it might lead to a completely unrelated spin-off that benefits society. You never know until you do it.
  • "Guinness is unique in having those mystical falling bubbles"

    I wouldn't say that it's unique. Lots of other Irish stouts and ales have the same effect. Lots of English bitters (ales) do it too: try pouring a can of Boddingtons.

    "Every loser worth his Stein knows that Guinnes is pressurized with nitrogen instead of carbon dioxide"

    Hmmm, are all of those others stouts and ales that I've seen doing it pressurised with N2 when on tap? ie. is it unique to just N2 powered drinks?
  • Just what the hell am I supposed to do with a simulation? I know what to do if I want to watch the bubbles in a Guinness!

    Well, if it were an Open Source simulation, you could adapt the code for an X screensaver.

    This proves that free as in freedom is better than free as in free beer.
  • I spoke with some marketing people from Guinness at a friend's wedding in the summer. It seems that they now have a widget in their bottles too. Unfortunately a couple of them exploded, so they haven't yet been able to release them!

    BTW, why does everybody here use knifes and things like that to open their Guinness cans? It's only thin metal: grab at both ends and rotate back and forth in opposite directions. It will soon tear open without needing much effort. Then again, maybe it's better to use something else as that leads to sharp edges that could slice open your hands as you twist the can!
  • Check the can: it's imported from Ireland. Dunno about the draught. Some countries (e.g. UK) brew their own Guinness under license, but I don't that includes the US.
  • On a semi-related issue, your glass has to be dirty for the bubbles to really kick in. If you have a clean-room grade glass, the CO2 has no particles to fixate on. It's very similar to the crystallization of solutions needing a 'seed' to start.
    ---
  • As a part time brewmeister, I wish to point out that this phenomenon can be replicated with any other beer. The important factor is that Guiness uses nitrogen instead of carbon dioxide. Nitrogen gas has a higher surface tension, hence the smaller bubbles are carried with the liquid flow. On occasion, I and other brewers carbonate with nitrogen and use it for dispensing. I can even make a pale ale emulate the Guiness effect. Nitrogen is more expensive than CO2 though.
    Bottoms Up.
  • This is getting a bit off topic, but what the hell :)

    I have a three-tap refridgerator for my homebrew, and I need to get arround to a fourth tap for the nitrogen mix for my stouts.

    Superior Manufacturing (I think; it's superior something :) sells in low quantities to individuals. A simple tap handle is about $30, and the Guinness-slow-thingy is about $100. You can usually get them from homebrew shops as well, but they all tend to buy from superior and double or triple the price anyway :)

    The expensive part is the CO2 cannister, but buy big; it will save you in the long term--filling a 20 lb cannister costs about a dollar more than a 5lb. On the other hand, it's not convenient to haul around . . .
  • Penenace completed, and I shall visit the tavern on the way home tonight just to make sure I still appreciate that magical little mug.
  • "Hmmm, are all of those others stouts and ales that I've seen doing it pressurised with N2 when on tap? ie. is it unique to just N2 powered drinks?

    I have only seen Guinness and Boddington's on N2 taps here in the states. I believe I saw others when I was in London, but I forget which ones. Possibky one of the Fuller's, but that would only be a guess.

    -d9
  • In about 1993, the US bottled version was changed for the worse--much worse. It was seriously watered, and I don't know what else.

    On the other hand, some yeast slipped through, and a friend cultured it, but I think my sample went bad years ago . . .

    Also, before ordering it on tap, check how long the keg's been open. Somewhere around three days seems to be the cutoff . . .
  • Do you really think that anyone who contributed to quantum mechanics was sober at the time?

    And then there's the coswine function from inebriated mathemeticians. Sine is from the unit cirecle, the hyperbolic sine from the unit hyerbola, and they'd had enough that they started working with the unit square . . .

  • Hmmm. Having known many a bartender in the past, I can assure you that they have no N2 bottle in the back pressurizing the kegs. The bubbles are made very small mostly due to the long rubbery thing that is at the very end of the tap. Inside that little tube is a set of screens, similar to aerators on kitchen taps. These screens make the bubbles smaller than North American beers, which don't have the special tap. So, if you have a relatively viscous beer (such as most stouts), you can give your homebrew the cascade (as most folks call it) by pouring the brew through a set of screens. Of course, you need to have a certain amount of pressure at the screens, so a funnel with a hose connected should be used to gravity feed the spout holding the screens. Incidentally, this setup can be used to add beautiful art to the head of the pint. Now that is a rare skill these days that this beer drinker truly appreciates!

    So, I would recommend using 3 to 5 0.05mm screens about 3mm apart, i.e. not touching so that the beer will flow properly. Then most of the bubbles will be of the correct size to cascade. Some will agglomerate, initiating the effect. I haven't tried it, so some experimentation with the number spacing and size of the screens as well as the amount of gravity potential will be necessary. I'm going to try it, and if I succeed, then I will try to get my results posted for all to use!

    About the widget - I suspect that that thing simply creates really small bubbles. I intend to check this hypothesis over the next week or so as well.

    About the study - I don't think that it really provided new insights, as I have known about the screens well before this study even began. I was told by someone who had known it for years. I suspect that the folks at Guiness have known it for decades. Still, to see it scientifically demonstrated in such a way will silence many a self-proclaimed beer scholar! The most important discovery in my opinion is the size of the bubble requuired for the cascade.

    One final observation - the argument that N2 sinks while CO2 rises makes no sense. CO2 is heavier (1.977 g/l) than N2 (1.2506 g/l), so if either sinks, it would be the CO2 before the N2. Of course, being a gas, they both are significantly more bouyant than the Guiness... I have heard this argument vehemently debated over many a pint of the world's finest stout.

  • It could be that by bringing the beer to such a low temperature, you are inadvertantly creating a supersaturated solution. The ability of water to absorb solute (i.e salt, sugar, etc) decreases with temperature. So, if you make a sulution at a high temperature (brewing process) and then bring it down to a signifigantly lower temperature, there is actually more solute in the solution than can really be maintained. Once you add the lime juice, you bump the solute amount just a little too far and the semi-dissolved solids in the lime juice create a "seed" for crystals to form around, just like a bit of dirt or salt can create a "seed" for a raindrop. What you are seeing as freezing may be a process of solute's in the beer crystalizing out from around the lime juice "seed" that you added.
    Does anyone remember the specifics of this process better? It's been a long time since 12th grade chem, and even longer since I paid attention to the guy who taught it to me.

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